While many of today's rivers, lakes and groundwater reservoirs continue to be
overexploited, a new report launched by leading scientists at the United Nations
Commission on Sustainable Development warns that unless steps are taken to improve
the way water is managed, twice the world's current water consumption may be needed
by 2050 to feed a global population of some 9 billion.

The scientists from the Stockholm International Water Institute (SIWI), International Food Policy
Research Institute (IFPRI), World Conservation Union (IUCN) and International Water Management
Institute (IWMI) said that the ambitious international commitment to halve the number of people
facing hunger have missed a fundamental question: Where is the water needed to grow the food to
feed future generations properly? The report, "Let It Reign: The New Water Paradigm for Global Food
Security" points out that feeding the world is in many ways a daunting water challenge.

Food security -- the enormous challenge

"The world needs more food and consumption is moving towards more water-intensive items and less
healthy diets. Irrigation can only partly satisfy the thirst for expanded future food production, and
agricultural land is shrinking," said Prof. Jan Lundqvist of Linköping University (Sweden), one of the
report's authors. "Global food security in the future requires a new water management approach
today." The report provides policy recommendations intended to facilitate such a new approach.

Today, 840 million people remain undernourished across the world. In 2025, the world will have 8
billion inhabitants, and 9 billion in 2050. The demand for food will increase with 50 percent every
generation. How big the increase ultimately will be depends in large part on the purchasing power of
consumers. According to the Food and Agricultural Organisation of the United Nations,
average demand will be 3000 kcal per person per day. Even considering wastage, the new report says
that if a high calorie intake becomes the social norm for all of humanity, the increased pressure on
natural resources -- above all, water, will be dramatic. An additional volume of water equal in size to
all of the water used in households, industry and agriculture today (5600 km3) would be required by
2025.

Agriculture is water-driven

This is because production of food is a highly water-consuming activity. In developing countries, the
report says, agriculture accounts for 70-90 percent of available freshwater supplies. It takes 550 litres of
water to produce enough flour for one loaf of bread -- a fraction of the roughly 1500 litres used to
produce 100 grams of grain-fed beef. Already in large parts of the world, water is the most limited
and most uncertain resource, both in food production and for different ecosystems. A fundamental
consequence for crops grown in the open landscape is that large quantities of water evaporate back
to the atmosphere from vegetation and soil, particularly in hot climate regions.

Although the world produces more food than ever, it has come at a cost: The drastic reduction of
water in a number of rivers and sinking groundwater levels around the world, according to the report. There is no water
flowing in the Yellow, Colorado and Indus rivers in large parts of the year. Previously large lakes, like
the Aral Sea and the Chad Sea, are now mere shadows of their former selves. Around 1.4 billion
people, nearly a quarter of the world's population, live near rivers where all of the available water is
committed. Other uncertainties exist: Some predict that the 40 poorest countries, with a total
population of some 1-3 billion, will lose on average up to a fifth of their cereal production potential in
the 2080s because of climate change.

These factors, combined with the growing needs of cities and industries for water, will minimize the
food gains resulting from increased or more effective use of irrigated water in agriculture. The most
promising solutions identified in the report come from rain-fed agriculture. Using rain more efficiently,
"rainwater harvesting," is a time-tested practice in some parts of the world that the report says needs
strong support to come into wider use. A more effective use of precipitation in combination with land
care has already led to a doubling of production in large parts of Africa. Also, better use of the
rainwater in the soil -- so-called "green water" can help fuel the agricultural revolution needed to end
hunger.